An operation that performs cauterization or “ablation” with use of an ablation catheter has been performed as one of medical treatments for arrhythmia, etc. Such ablation that uses the ablation catheter may be performed on a site that involves the arrhythmia inside the heart, for example. In general, methods of the ablation may be roughly classified into a method that performs heating and a method that performs cooling. More specifically, the methods of the ablation may be roughly classified into a high-temperature ablation that uses a high frequency current and a low-temperature ablation that uses liquid nitrous oxide, liquid nitrogen, etc. When performing the ablation of a site such as the posterior wall of the left atrium of the heart by means of the ablation catheter, i.e., upon surgical ablation of the left atrium, the esophagus located in the vicinity of the posterior wall of the left atrium may typically be heated or cooled as well, leading to a possible damage of the esophagus.
To address this, a method has been proposed that measures or monitors information on a temperature in the esophagus, such as a temperature of the medial wall of the esophagus. The method involves insertion of a temperature measuring catheter or a so-called “esophageal catheter” into the esophagus through the nose of a patient by means of a transnasal approach. For example, reference is made to Patent Literatures 1 and 2. The temperature measuring catheter includes a temperature sensor in the vicinity of a metal ring located near a tip of a catheter tube. The temperature sensor measures a temperature in the esophagus. A system that achieves such a method, or a “catheter system”, includes the foregoing temperature measuring catheter and a temperature measuring apparatus that measures the temperature in the esophagus by means of the temperature sensor of the temperature measuring catheter.
Monitoring the temperature in the esophagus in such a manner makes it possible to avoid the possible damage of the esophagus upon, for example, the foregoing surgical ablation of the left atrium.